Anxiety, fear, and stress play major roles or contribute in some way to many human and non-human animal behavioral disorders. For example, with regard to canines and felines, storm phobias, noise phobias, social avoidance, fear-related aggression, compulsive disorders, and submissive urination have obvious anxiety components, but even problems such as urine marking, territorial aggression, and resource guarding can be fueled by fear or anxiety. Fear and anxiety disorders affect an estimated 23 million dogs in the US at a cost of more than $1 billion in treatment and property damage. Of dogs relinquished to shelters, perhaps 40% or more are abandoned due to behavioral issues, while 14% of cats are surrendered due to behavioral problems. In pet cats, behavior problems are still the most common cause of euthanasia. In a recent survey of pet owners, 41% of dog owners reported that they have owned a dog with anxiety issues at some time, with 29% of currently-owned dogs being affected. The most prevalent types of anxiety reported by these owners included noise phobia (17%), separation anxiety (13%), and generalized anxiety (5%).
Anxiety in horses is similarly a common problem in the equine industry, contributing to behavioral problems, training issues and poor performance. In some cases, increased levels of anxiety are associated with health related issues such as gastric ulcers, which have been shown in some studies to impact a large percentage of horses. Manifestations of anxiety in horses is commonly seen not only in the form of gastric ulcers, but also is expressed behaviorally in the form of bolting, jumping, panicking, trailering difficulties, pacing, stall weaving, pawing, and biting. The most common risk factor for anxiety disorders in dogs appears to be acquisition from animal shelters or multiple foster homes, with up to 68.3% of dogs adopted from shelters exhibiting some type of anxiety disorder. One retrospective study on behavior diagnoses indicates possible breed predilections in Dalmatians, English springer spaniels, German shepherd dogs, and mixed breed dogs, while another study suggests cocker spaniels, schnauzers, and dachshunds may be at risk for developing separation anxiety. The incidence of anxiety disorders does appear to increase with age, most likely due to a loss of cognitive function, from an incidence of 22.5% in dogs less than 3 years of age to an incidence of 36.5% in dogs 8 years of age and over.
Fear is an emotional response due to the presence of a specific stimulus (object, noise, individual, etc.) that the pet perceives as a threat or a danger. In contrast, an anxiety is a reaction of apprehension or uneasiness to an anticipated danger or threat. Anxiety, therefore, may be displayed in the absence of an identifiable stimulus, whereas with fear, a stimulus can usually be identified. While anxiety and the accompanying physiological stress are unlikely to be pathologic in the short-term, when stress and anxiety become a chronic state, the health, welfare, and lifespan of the pet may become compromised. Therefore, to provide optimum health and welfare for all pets, veterinary healthcare practitioners consider anxiety as an additional possible disease state in companion animals. At the extreme end of the spectrum, a phobia is a profound, excessive, abnormal fear response that occurs without the presence of a true threat or is out of proportion to the needs for dealing with an actual threat. While fears may be normal adaptive responses, phobias are abnormal, maladaptive, and typically interfere with normal function. Anxiety, which inhabits the middle of the spectrum, is often overlooked or misunderstood, but may have a significant impact on a pet's daily well-being.
Clinical signs of fear and anxiety in dogs include hypervigilance, elimination, destruction, excessive vocalization, hyper-salivation, panting, hiding, trembling, and escape behaviors. In cats, chronic anxiety and fear can also lead to secondary behavioral problems such as over-grooming, spraying, and inter-cat aggression, and can predispose the cat to health problems owing to a compromised immune system. Since most of the clinical signs of fear and anxiety are destructive and distressing to both pet and owner, one can easily understand why pet owners would be likely to seek out advice for such disorders. Not coincidentally, the most common risk factors for relinquishment to animal shelters and euthanasia for both dogs and cats include house-soiling, destruction, aggression, and hyperactive behavior—all potential clinical signs of anxiety.
Anxiety disorders rarely occur alone, and often occur in combination. Thunderstorm and noise phobias do not necessarily occur simultaneously; however, thunderstorm phobia, noise phobia, and separation anxiety occur significantly more often together than would be expected were these conditions independent. Such evidence suggests that the precise cause of a pet's anxiety could be difficult to isolate, and multiple pathologies could be occurring in the same pet.
Although the “triggers” and manifestation of behavioral disorders in humans may be different, anxiety, fear, and stress contribute to the human disorders. In an effort to alleviate the behavior disorders of human and non-human animals, certain synthetic drugs have been developed. For instance, clomipramine hydrochloride, fluoxetine hydrochloride, benzodiazepine, and acepromazine maleate are all drug compositions that have been used in an attempt to alleviate anxiety in humans and/or non-human animals. While these drugs may provide some relief from anxiety, a significant downside of these drugs is that they can be sedating, and the human or non-human animal experiences lethargy or sleepiness. Moreover, many of these drugs are synthetic compositions, which humans may be reluctant to ingest or administer to their pets.
The biochemistry of anxiety is extremely complicated and, to a great extent, still poorly understood. Studies have shown that nearly every type of neurotransmitter and hormone, from serotonin, γ-aminobutyric acid (GABA), glutamate, and dopamine to cortisol, adrenaline, and even thyroid hormone can play some role in anxiety. Anxiety, in many ways, is simply the biochemical reaction to brain stress. When something causes any change to the delicate chemical balance in the brain, anxiety is often the result.
The ideal management for anxiety, therefore, should be multi-modal, increasing the likelihood that one or more of the mechanisms of action will target and correct any given underlying chemical imbalance. Common FDA-approved pharmaceuticals such as serotonin-selective re-uptake inhibitors (SSRI's), tricyclic antidepressants (TCA's), and benzodiazepines, however, typically work via a single mechanism of action.
Due to the difficulty in tracking adverse drug reactions in combination drugs, the FDA has become increasingly reluctant to approve drugs with multiple active ingredients. Therefore, a multi-modal approach using pharmaceuticals alone is unlikely. Nutritional and herbal supplements, which are regulated more like foods than drugs by the FDA, represent a novel delivery method for multiple ingredients, offering a much greater opportunity for the multi-modal management of anxiety. For this and other reasons, the use of natural products for human and non-human animals is becoming increasingly popular as consumers seek alternatives to pharmaceuticals. Some of these natural products are being incorporated into dietary supplements and various foods.
In light of the discussion above, the need exists for a natural product composition that has anxiolytic properties. This composition should help support normal behavior and facilitate a calming effect, while not causing extreme lethargy or sleepiness. In turn, such compositions should work synergistically to manage and control the clinical signs or symptoms of anxiety.